RP2040 SDK PWM example Take 2

/*
    Raspberry Pi Pico PWM example

    Scott Beasley (2021) No Copyright.

    Code used by Damien P. George Copyright (c) 2020
    From the RPI Pico MicroPython project. See below for copyright info.
    https://github.com/raspberrypi/micropython/blob/pico/ports/rp2/machine_pwm.c
*/

#include "pico/stdlib.h"
#include <stdio.h>
#include "pico/time.h"
#include "hardware/pwm.h"
#include "hardware/clocks.h"

#define LED_PIN 25
#define PWM_PIN 16
#define DUTY_50_PCT 32767
#define PWM_1KHZ 62500  // Wrap val for 1khz at SYSCLK / 2
// Not worring about less than 1k for now.

int set_pwm_duty (uint slice, uint channel, uint32_t top, uint32_t duty);

int main (void)
{
    uint32_t div = 0, top = 0;
    uint slice_num, channel;

    // Use the LED for error notifications
    gpio_init (LED_PIN);
    gpio_set_dir (LED_PIN, GPIO_OUT);

    slice_num = pwm_gpio_to_slice_num (PWM_PIN);
    channel = pwm_gpio_to_channel (PWM_PIN);
    gpio_set_function (PWM_PIN, GPIO_FUNC_PWM);

    // Div the sys clock by 2
    pwm_set_clkdiv (slice_num, (float)2 * 1.0f);

    // Set the PWM counter wrap value to reset on
    top = PWM_1KHZ / 50;  // Set for 50khz freq - Close to it anyway.
    pwm_set_wrap (slice_num, top);

    while (1) {
        tight_loop_contents ( );
        set_pwm_duty (slice_num, channel, top, (uint32_t)DUTY_50_PCT);
        sleep_ms(2000);
        set_pwm_duty (slice_num, channel, top, (uint32_t)DUTY_50_PCT / 2);
        sleep_ms(2000);
        set_pwm_duty (slice_num, channel, top, (uint32_t)DUTY_50_PCT / 4);
        sleep_ms(2000);
        set_pwm_duty (slice_num, channel, top, (uint32_t)DUTY_50_PCT / 6);
        sleep_ms(2000);
    }
}

// Code used from https://github.com/raspberrypi/micropython/blob/pico/ports/rp2/machine_pwm.c
// Function - machine_pwm_duty_u16
// Shaped for my needs (Scott Beasley) No Copyright.
// MIT License (MIT) Damien P. George Copyright (c) 2020
int set_pwm_duty (uint slice, uint channel, uint32_t top, uint32_t duty)
{
    // Set duty cycle.
    uint32_t cc = duty * (top + 1) / 65535;
    pwm_set_chan_level (slice, channel, cc);
    pwm_set_enabled (slice, true);

    return 0;
}